1 files changed, 19 insertions, 0 deletions
diff --git a/modules/markup/markdown/color_util.go b/modules/markup/markdown/color_util.go
new file mode 100644
index 0000000..355fef3
--- /dev/null
+++ b/modules/markup/markdown/color_util.go
@@ -0,0 +1,19 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markdown
+
+import "regexp"
+
+var (
+	hexRGB = regexp.MustCompile(`^#([0-9a-f]{3}|[0-9a-f]{6}|[0-9a-f]{8})$`)
+	hsl    = regexp.MustCompile(`^hsl\([ ]*([012]?[0-9]{1,2}|3[0-5][0-9]|360),[ ]*([0-9]{0,2}|100)\%,[ ]*([0-9]{0,2}|100)\%\)$`)
+	hsla   = regexp.MustCompile(`^hsla\(([ ]*[012]?[0-9]{1,2}|3[0-5][0-9]|360),[ ]*([0-9]{0,2}|100)\%,[ ]*([0-9]{0,2}|100)\%,[ ]*(1|1\.0|0|(0\.[0-9]+))\)$`)
+	rgb    = regexp.MustCompile(`^rgb\(([ ]*((([0-9]{1,2}|100)\%)|(([01]?[0-9]{1,2})|(2[0-4][0-9])|(25[0-5]))),){2}([ ]*((([0-9]{1,2}|100)\%)|(([01]?[0-9]{1,2})|(2[0-4][0-9])|(25[0-5]))))\)$`)
+	rgba   = regexp.MustCompile(`^rgba\(([ ]*((([0-9]{1,2}|100)\%)|(([01]?[0-9]{1,2})|(2[0-4][0-9])|(25[0-5]))),){3}[ ]*(1(\.0)?|0|(0\.[0-9]+))\)$`)
+)
+
+// matchColor return if color is in the form of hex RGB, HSL(A) or RGB(A).
+func matchColor(color string) bool {
+	return hexRGB.MatchString(color) || rgb.MatchString(color) || rgba.MatchString(color) || hsl.MatchString(color) || hsla.MatchString(color)
+}